<!DOCTYPE html>
<title>background-position-x animation while running</title>
<style>
@keyframes holdBackgroundPosition {
  from,to { background-position-x: 50%; }
}
#test {
  height: 100px;
  width: 100px;
  background-repeat: no-repeat;
  background-image:url(); /* a 25x25 px red box */
  background-position-x: 0px;
  animation: holdBackgroundPosition 100s infinite;
}
</style>
<div id="test" class="reftest-opaque-layer"></div>
